Electric control unit



O ct. 24, 1950 R. A. HAIGH 2,527,061

ELECTRIC CONTROL UNIT Filed Oct. 14, 1947 PIU/ARD A. f/n/GH PatentedOct. 24, 1950 ELECTRIC CONTROL UNIT Richard A. Haigh, Brighton, Mich.,assignor to Automatic Controls Corporation, Ann Arbor, Mich., acorporation of Michigan Application October 14, 1947, Serial No. 779,745

Claims.

This invention relates to improvements in electric control units, moreparticularly units adapted for either making or breaking an electriccircuit for a certain length of time once during a predetermined periodof time, as for example a day of twenty-four hours. One eld of use is inthedefrosting of electric refrigerators.

One of the objects of the invention is the provision of apparatus forthe purpose stated which shall be rugged, operable in any position,simple and consequently of low cost.

Another object is 'the provision of a novel means for actuating thecontrol switch from the rotating hour shaft of a clock mechanism.

A further object is the provision of means for mounting the severalparts of the mechanism simply, rigidly and compactly upon a wall of thecasing of a unit which may be plugged directly in a wall for floorsocket or receptacle.

Still another object is the provision of means for quickly and easilysetting the clock mechanism to correspond with the time of day when itis put in operation and for selecting the time of day when the switchshall be actuated.

Other objects and features of novelty will appear as I proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, I have illustrated in the accompanyingdrawing, in which Fig. l is a side view of a unit embodying theinvention.

Fig. 2 is a front View thereof.

Fig. 3 is a longitudinal sectional view taken substantially on the line3-3 of Fig. 4.

Fig. 4 is a transverse sectional View taken substantially along the line4-4 of Fig. 3 showing the switch actuating mechanism in inoperativeposition.

Fig. 5 is a fragmental view similar to Fig. 4 showing the switchactuating mechanism in operative position, and

Fig. 6 is a detail sectional View on a larger scale, the view beingtaken substantially along the line 6 6 of Fig. 3.

In the drawing there is shown a casing of insulating material comprisinga flat wall or base III and a cover I I which may include a cylindricalside wall and an end Wall integral therewith. rlhe cover may be securedto the fiat wall I0 by screws I2 which extend through the flat wall andare threaded into tapped openings I3 formed in bosses I4 on the innerside of the cover.

The unit embodies a clock mechanism. For obvious reasons a clock drivenby a synchronous electric motor is preferred. Such a clock is illus-Lll) ,Fig 3.

2 trated herein but not in deail. It comprises a field magnet I5 whichis attached by suitable means to bosses I6 on the casing wall I0. motorrotor and the clock gearing are enclosed in a housing I6 carried by themagnet I5. The magnet winding is indicated at I'I.

A sheet metal bracket I8 of brass preferably is carried by the magnetI5, being supported thereupon by screws I9 and 20 threaded kinto therespective ends of a pair of spacing columns 2i. The hour shaft 22 ofthe clock mechanism extends through an opening in this bracket. Rigidlymounted on the bracket parallel with the motor shaft 22 there is a post23 upon which is rotatably and slidably mounted a hollow shaft 24carrying at its lower or inner end a wheel 25. The upper portion ofhollow shaft 24 is counterbored. Post 23 is bored and tapped to receivea screw 26 the head of which forms a stop r2'I for engagement with theshoulder in the shaft formed at the base of the counterbore. A coilspring 28 biases the hollow shaft 24 upwardly and holds it against thestop 21. Hollow shaft 24 extends upwardly through a hole 29 in the flatend wall of the casing cover, as shownin On its outer extremity there ismounted a handle pointer 30 which may be adjusted angularly to anydesired position after a setscrew 3I is loosened.

In the periphery of wheel 25 there are a series of pockets or notches 32which have circular contours. These notches are adapted to be engaged bya round headed lug 33 fixed in the hour shaft 22 of the clock mechanism.Preferably this lug is in the form of a pin which is press fitted into atransverse hole in the shaft. As it turns in the direction indicated bythe arows in Figs. 4 and 5 it engages a notch as indicated in Fig. 4 andadvances the wheel a distance corresponding to the spacing of thenotches. In they illustrated example there are twenty-four notches 32,and hence the wheel 25 makes one complete revolution every twenty-fourhours. Through a considerable part of each revolution of the hour shaft22 the lug 33 is out of engagement with the wheel 25, and it isnecessary at such times to hold the Wheel against rotation. This Iaccomplish by use of a spring detent 35 mounted on the bracket I8 havingav curved extremity adapted to ride into and out of the notches 32 asthe wheel turns. The mechanism illustrated for driving hollow shaft 24vwill be referred to hereinafter as a Geneva motion mechanism.

On the bracket I8 I also mount an electric switch, preferably amicroswitch of knownform Thev ' normal position.

contained in a switch housing 3@ and having a plunger 3l. A mountingscrew 3S extends through housing 36 and is threaded into a tapped holein the bracket I8. A second threaded fastening 39 extends through thehousing 33 and into an arcuate slot 4U in bracket I8, see Fig. 4. Bythis means I am enabled to provide limited adjustment or". themicroswitch by loosening the fastening 39 and tightening it again whenthe adjustment is accomplished.

The microswitch includes a leaf spring actuator 4l having the normalposition illustrated in Fig. 4 and adapted to operate the plunger. 3l asit is swung down to or away from the position of Fig. 5. This actuatoris moved by an abutment 42 attached to wheel 25 and thus turns in acircular path. As this abutment travels through the lower part of itsorbit it wipes against the spring 4|, moving the latter first to switchactuating position and then away from. that position, nally leaving thespring and permitting the switch plunger 31 to again rise to its Thelength of time during which the switch is in actuated position may bevaried to some extent by changing the length of the spring 4|. As iswell understood in the art, switches of this type may be set either tomake or to break a circuit when the switch is actuated.

In the wall ill of the casing are mounted two bus bars 44 and 45 whichcarry prongs fifi and 41 extending through the wall lf3 and adapted tobe received in a wall or floor receptacle. They are spaced from thecenter of wall I5 so that when they are inserted in a` wall receptaclethe center of gravity of the unit tends to swing it inward toward theWall in which the receptacle is mounted.

Bracket I8V has a downturned lip 43 from which is supported a receptacleor plug socket 49 by suitable means including a screw 5D. Thisreceptacle extends laterally away from the motor through an opening 5lin the side wall ii of the cover. Preferably this receptacle is providedwith a flange 52 which overlaps opening 5i on three sides and thus helpsto tie together the bracket I8 and the cover of the casing. In order toclose the opening 5l below receptacle the base or at wall l0 of thecasing is provided with an upstanding arcuate portion 53 which is ushwith the cover wall when the parts are assembled and which stands justbeneath and may abut the receptacle 4S.

Bus bar 45 is connected with a conductor which leads to one terminal or"the microswitch, From the other terminal thereof a conductor 53 leads toone terminal of receptacle 4t, and from the other terminal of thatreceptacle a conductor 51 extends back to the other bus -bar 44. Thecircuit for the receptacle 49 therefore includes and is controlled bythev microswitch. The clock motor of course may take its current alsofrom the bus bars 44 and 45 by suitable connections, not shown.

Surrounding the hollow shaft 24 on the outside of the casing end wallthere is a dial 88 marked with divisions equal to the number of notches32. In the illustrated case there are twenty-four divisions comprisingtwo series of divisions each numbered l to l2 inclusive, one seriesbeing marked Night and the other being marked Day. Preferably this dialis imprinted upon a separate plate of insulation Si which is secured tothe casing by screws E2 or the like. In the normal position of thehollow shaft. 24 a space 63 is left between the handle pointer 3i) andthe top of plate 6|.

Operation. When the unit is to be installed, for example in the linesupplying power to a refrigerator, the operator first makes sure thatthe wheel 25 is in the position at which the actuation of the switchbegins to take place. This may be accomplished by plugging the unit intoa house receptacle convenient to the refrigerator, connecting a testingline to the receptacle 49, and turning the handle clockwise until thecurrent in the testing line goes oif. This corresponds to the -beginningof the defrosting period. The operator then loosens setscrew 3| andturns the handle pointer 30 to point to the dial indication of the timeof day or night at which the user desires to have the defrosting periodcommence, after which the operator tightens screw 3| in order to holdthe handle pointer against rotation relative to hollow shaft 24. Nextthe operator presses down on the handle Sil, which depresses theV wheel25, forcing it out of engagement with the lug 33. With the handle thusdepressed the operator turns it untilV it points to the dial indicationcorresponding to the then correct time of day or night, when he releasesthe handle enabling the spring 28 to return the wheel 25 to engagementwith the driving lug 33. He then removes the test line and puts the plugon the end of the refrigerator cord into the receptacle 4S of the unit.Current is thereby supplied to the refrigerator as needed, and the clockmotor is started. The clock shaft 22 turns once each hour and during acertain portion of each revolution it advances the wheel 25 one notch.When the abutment 42 wipes over the leaf spring actuator 4I it actuatesthe microswitch to open the refrigerator circuit, which remains openlong enough to defrost the refrigerator coils, alter which the abutment42 leaves the actuator 4i and the latter springs back to its Fig. 4position again establishing the refrigerator circuit. A small Variationin the period of actuation of the switch may be accomplished byloosening the fastening 39 and moving the switch housing through a smallangle about the clamping screw 38.

In the foregoing description I have necessarily gone somewhat intodetail in order to explain fully the particular embodiment of theinvention herein illustrated, but I desire it to be understood that suchdetails of disclosure are not to be construed as amounting tolimitations, except as they may be included in the appended claims.

Having thus described my invention, I claim:

1. In an electric control unit, a casing, a clock therein having an hourshaft, a second shaft parallel to said hour shaft and projecting throughsaid casing, Geneva motion mechanism comprising a lug on said hour shaftand a wheel on said second shaft provided with notches adapted tocooperate with Said lug for rotating said wheel once every twenty-fourhours, an electric switch, means comprising an abutment turning withsaid second shaft for actuating said switch, a twentyfour hour dial onthe outer side of said Icasing surrounding said second shaft, a pointeradapted to be secured in any angularly selected position on said secondshaft exteriorly of the casing, said second shaft being movablelengthvise to shift said wheel out of the plane of said lug, wherebywith the abutment in switch actuating position the pointer may beadjusted on the second shaft to indicate on the dial the time of dayselected for switch actuation, after which the pointer and second shaftmay be shifted lengthwise momentarily and adjusted angularly to indicateupon the dial the time of day at which the controller is put inoperation.

2. In an electric control unit, a casing comprising a fiat wall and acover, a synchronous motor attached to said flat wall, a bracket rigidlysupported upon said wall, said motor having an hour shaft extendingthrough an opening in said bracket, a post fixed in said bracketparallel with said motor shaft, a hollow shaft rotatable upon said post,a wheel on said hollow shaft, a Geneva motion connection between saidmotor shaft and said wheel for turning the latter once every twenty-fourhours, a pair of metal prongs fixed in and projecting from said flatwall, an electric switch mounted on said bracket, an abutment on saidwheel adapted to operate said switch, a plug socket fixed with respectto said bracket and flat wall and extending 4laterally of said motor andan electric circuit including said prongs, said switch, and theterminals of said socket, said cover having an opening therethrough toaccommodate said hollow shaft'and another opening to expose the surfaceof said socket.

3. In an electric control unit, a bracket, a clock xed with respect tosaid bracket having a rotating hour shaft, a second shaft parallel tosaid clock shaft, Geneva motion mechanism for rotating said second shaftfrom said clock shaft, a support pivotally mounted at one end upon saidbracket, an electric switch on said support, a leaf spring actuatorcarried by said support, an adjustable connection between said bracketand the opposite end of said support permitting the support to be swungon its pivot toward and away from said second shaft, an abutment turningwith said second shaft contacting said spring actuator once for eachrevolution of said second shaft, whereby adjustment of said support onits pivot moves said actuator toward or away from the circular path ofmovement of said abutment to vary the length of time during which saidabutment and spring actuator are in contact.

4. In an electric control unit, a casing, a clock mounted therein havinga rotating hour shaft, a second shaft parallel to sai-d clock shaftextending through an opening in the casing, a time dial fixed on thecasing surrounding said shaft, Geneva motion mechanism comprising aprojection of said clock shaft, and a wheel on said second shaft, saidwheel having a plurality of evenly spaced peripheral notches adapted tocooperate with said projection for rotating the second shaft, anelectric circuit, a switch therein biased toward closed position, meanscomprising an abutment turning with said second shaft for opening saidswitch temporarily, said second shaft being slidable lengthwise to shiftsaid wheel out of the plane of said lug, and a pointer on the outer endof said second shaft adapted to be secured in any angularly selectedposition on said shaft, whereby the angular position of said pointer atthe time of the opening of said switch may be set for any Selected timeof day and whereby the pointer may be set to indicate on said dial thecorrect time of day when the unit is installed.

5. A control unit as defined in claim 4, characterized in that a stop isprovided to limit the sliding motion of said shaft in one direction anda spring is provided to hold the shaft yieldably against said stop.

RICHARD A. HAIGH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,926,652 Rosenfeld Sept. 12,1933 2,224,593 Brown et al Dec. 10, 1940 2,346,694 Maris Apr. 18, 1944

